Blender Git Loki

Use darker lines, Change grid line spacing

VSE: Don't draw time grid lines

Add overlay option to disable grid drawing.
Reuse drawing code from other editors (timeline editor)
Add argument `display_minor_lines` to function `UI_view2d_draw_lines_x__discrete_frames_or_seconds`
This way minor line drawing can be disabled and so it doesn't cause too much visual noise.

{F10224091,size=full}

Differential Revision: https://developer.blender.org/D11790